Study of the Efficiency of Methods for Enhanced Condensate Recovery, Based on Reservoir Simulation Models

Abstract

Abstract The purpose of this paper is to assess the technological efficiency of methods for increasing condensate recovery from the Achimov deposits of the Urengoy Oil and Gas Condensate Field (Аch52-3 reservoir within the East Urengoy License Area). The distinctive features of the Achimov reservoirs are the low permeability (of the order of 1 mD) and abnormally high initial reservoir pressure (≈ 600 atm.). The technological performance was simulated using the ECLIPSE 300 composite flow model. To simulate the condensate recovery improvement methods at one of the Аch52-3 sections, the authors selected a development element the average parameters of which corresponded to the parameters of a full-scale model. The performance of various methods was evaluated by comparing the selected methods to the baseline scenario, which represents a traditional gas development process, i.e. the depletion. The methods for maintaining reservoir pressure by injecting various agents into the reservoir were considered as alternative scenarios for reservoir engineering: dry gas (cycling), nitrogen, water, WAG. In addition, the optimal ratio of injection and production wells, the voidage replacement, and gas recovery rate were selected. The economic efficiency of various development scenarios was estimated using an economic model. The complex approach was used to rank the options, taking into account both the technological results (gas / condensate recovery ratios) and economic indicators (NPV, state discounted revenue). The results of the studies on condensate recovery improvement confirm the technological applicability of unconventional technologies for the development of gas condensate fields, in particular, injection of nitrogen into the reservoir. These technologies make it possible to achieve a relative increase in condensate recovery by 40-50% compared to the baseline scenario. On the other hand, under current macroeconomic conditions, the conventional depletion method for gas-condensate recovery remains more attractive.